1. Field of the Invention
The present invention relates to venipuncture devices having a stylet needle which fits telescopically within a catheter and more particularly to needle restraining apparatus for preventing longitudinal movement of the stylet needle relative to the catheter during venipuncture.
2. The Prior Art
Venipuncture devices of a type having a rigid stylet needle which fits telescopically within a catheter are well known in the prior art. Typically, this type of venipuncture device is designed so that a beveled point of the stylet needle extends through the distal end of the catheter of the device. In this manner, the sharp beveled point of the stylet needle is used to break the patient's skin when making a venipuncture. Once the venipuncture has been made, the stylet needle can then be withdrawn through the catheter thereby leaving only the catheter within the patient's arm. Suitable tubes for purposes of intravenous feeding, collecting blood samples, transfusions or the like can then be connected to the hub of the tube adaptor of the catheter. Examples of this type of device are illustrated in U.S. Pat. No. 3,875,938.
In using the type of venipuncture device described above to make a venipuncture in a patient's arm, it frequently happens that the person using the device holds it at or near the hub of the tube adaptor of the device. This is the logical place to hold the device since it is closest to the beveled point of the stylet needle, thereby affording a more accurate and controlled insertion of the needle. However, when the venipuncture device is held as indicated by the tube adaptor, as the user attempts to make a venipuncture in the patient's skin, a rearwardly directed force is applied to the stylet needle causing it to slip through the catheter and tube adaptor until the beveled point of the stylet needle is obscured. This greatly increases the difficulty and pain associated with making a venipuncture since the catheter may become damaged and be undesirable for insertion through the patient's skin.
In order to prevent the stylet needle from sliding through the catheter of the device while making a venipuncture, it is necessary for the person using a conventional venipuncture device to hold it further back from the exposed beveled point of the needle at or near the hub of the needle. However, when holding the venipuncture device by the hub of the needle, it becomes very difficult to make an accurately controlled insertion into a vein in the patient's arm because the device is held at a point that is distant from the point of the needle.
Until this present invention, there has not been a venipuncture device available which combined the advantages of preventing the stylet needle of the device from being pushed back through the catheter of the device during venipuncture while at the same time allowing the user to hold the device by the tube adaptor near the distal end of the needle thereby maintaining the accuracy with which the point of the needle can be inserted into a vein in the patient's arm.